Epoxy resin composition and production process thereof

ABSTRACT

An epoxy resin composition comprising: 
     (A) 1 to 40 parts by weight of a modified low molecular weight polyolefin obtained by graft copolymerizing at least one graft monomer selected from the group consisting of: 
     (i) at least one unsaturated carboxylic acid derivative selected from the group consisting of unsaturated carboxylic acids and anhydrides thereof and esters thereof, 
     (ii) at least one aromatic vinyl compound, and 
     (iii) at least one nitrile compound, onto a low molecular weight polyolefin having an inherent viscosity [η] of 0.01 dl/g to 1.0 dl/g, as measured in decalin at a temperature of 135° C., 
     (B) 99 to 60 parts by weight of an epoxy resin (the total amount of (A) and (B) is 100 parts by weight), 
     (C) a hardener for epoxy resin, and optionally 
     (D) 0.01 to 20 parts by weight of a monoamine compound. 
     This epoxy resin composition has an improved impact resistance, water resistance, anti-rust property, antioxidant property, chemical resistance, substantially without impairing the adhesiveness inherent in the epoxy resin.

TECHNICAL FIELD

The present invention relates to an epoxy resin composition and aproduction process thereof. More specifically, it relates to an epoxyresin having improved properties such as impact resistance, waterresistance, rust resistance, oxidation resistance, chemical resistance,substantially without impairing the adhesiveness of the epoxy resin, byformulating a modified low-molecular weight polyolefin having at leastone member selected from the group consisting of (i) unsaturatedcarboxylic acids and acid anhydrides thereof and esters thereof, (ii)aromatic vinyl compounds and/or (iii) nitrile compounds, graftedthereon, into a conventional epoxy resin or by formulating thereinto amonoamine compound, and to a production process thereof.

BACKGROUND ART

Hereinbefore, epoxy resins have been generally and widely used in thefields of, for example, adhesives, paints, coating agents for surfaceprotection. Such epoxy resins, although having an excellent adhesivenessto metals, woods and other materials, have a drawback in that theygenerally have an inferior impact resistance and, therefore, cracks maybe formed upon impact during use, or phenomena such as peel-off mayoccur. To eliminate these drawbacks and improve other various propertiesthereof, various compositions comprising polymers having a low glasstransition point formulated into epoxy resins have been proposed. Forexample, Japanese Unexamined Patent Publication (Kokai) No. 54-83097filed by the present Applicant discloses a composition containing aspecific modified low molecular weight polyolefin formulated thereinto,which has an improved water resistance and chemical resistance. However,further research and a development of the improvement in the impactresistance is needed.

On the other hand, Japanese Unexamined Patent Publication (Kokai) No.51-551 discloses a composition comprising an ethylene copolymercontaining an epoxy group. Although the impact resistance of thiscomposition is considerably improved, because of the high molecularweight of the modifier, the problems arise of a compatibility with theepoxy resin, a lowering of workability due to an increased viscosity,and the final appearance of the applied coating.

Also, Japanese Unexamined Patent Publication (Kokai) No. 55-84335discloses a composition comprising a modified liquid polyisoprene rubberto which maleic anhydride or a derivative thereof is added, an epoxyresin and a curing accelerator. However, under the conditionsspecifically shown in the Example, the reaction between the modifiedliquid polyisoprene and the epoxy resin is insufficient and acomposition having a poor adhesiveness and impact resistance isproduced.

Further, Japanese Unexamined Patent Publication (Kokai) No. 57-98535discloses an epoxy resin composition containing a maleated polybutadieneand a tertiary amine formulated thereinto, but this is not practicalbecause the surface hardness and heat resistance are greatly reduced.

As described above, in epoxy resin compositions of the prior art,because of the high molecular weight of the modifier which is added toimprove the impact resistance, the compatibility with the epoxy resin isgenerally not good, and an increase of the viscosity occurs when thecomposition is used in the molten state or the solution state, wherebythere arise drawbacks such as the lower workability when formed intoconventional paints or adhesives and an inferior appearance of theapplied coating when formed into a composition for powdery paint.Furthermore, these epoxy resin compositions cannot be considered to havea satisfactory improvement of the impact resistance, and a furtherdevelopment of the water resistance, rust resistance, oxidationresistance, and chemical resistance, is necessary.

DISCLOSURE OF THE INVENTION

Accordingly, an object of the present invention is to provide an epoxyresin composition having improved characteristics such as impactresistance, water resistance, rust resistance, oxidation resistance,chemical resistance, without impairing the adhesiveness of the epoxyresin, and the production process thereof.

That is, in accordance with the present invention, there is provided anepoxy resin composition comprising:

(A) 1 to 40 parts by weight of a modified low molecular weightpolyolefin obtained by graft copolymerizing at least one graft monomerselected from the group consisting of:

(i) at least one unsaturated carboxylic acid derivative selected fromthe group consisting of unsaturated carboxylic acids and anhydridesthereof and esters thereof,

(ii) at least one aromatic vinyl compound, and

(iii) at least one nitrile compound, onto a low molecular weightpolyolefin having an intrinsic viscosity [η] of 0.01 dl/g to 1.0 dl/g,as measured in decalin at 135° C.,

(B) 99 to 60 parts by weight of an epoxy resin (the total amount of (A)and (B) is 100 parts by weight), and

(C) a hardener for the epoxy resin.

According to the present invention, there is also provided a process forproducing an epoxy resin composition containing the components (A), (B)and (C), which comprises kneading the above-mentioned components (A) and(B) while heating, to make the unreacted amount of the component (B),based upon 100 parts by weight of the component (A), 1 part by weight orless, and then formulating the mixture with the hardener (C) at atemperature not higher than the hardening temperature of the hardener(C).

According to the present invention, there is further provided an epoxyresin composition comprising:

(A) 1 to 40 parts by weight of a modified low molecular weightpolyolefin obtained by graft copolymerizing at least one graft monomerselected from the group consisting of:

(i) at least one unsaturated carboxylic acid derivative selected fromthe group consisting of unsaturated carboxylic acids and nnhydridesthereof and esters thereof,

(ii) at least one aromatic vinyl compound, and

(iii) at least one nitrile compound, onto a low molecular weightpolyolefin having an inherent viscosity [η] of 0.01 dl/g to 1.0 dl/g, asmeasured in decalin at 135° C.,

(B) 99 to 60 parts by weight of an epoxy resin (the total amount of (A)and (B) is 100 parts by weight),

(C) a hardener for the epoxy resin, and

(D) 0.01 to 20 parts by weight of a monoamine compound.

According to the present invention, there is still further provided aprocess for producing an epoxy resin composition containing thecomponents (A), (B), (C) and (D), which comprises reacting theabove-mentioned components (A), (B) and (D) by kneading, while heating,and then formulating the hardener (C) at a temperature not higher thanthe hardening temperature of the hardener (C).

BEST MODE FOR CARRYING OUT THE INVENTION

The composition according to the present invention has both an excellentimpact resistance and adhesiveness and, when employed as the compositionfor a powdery paint, has a good pulverizability of the composition,blocking can be prevented, and an applied coating having an excellentappearance can be obtained. Also, due to a good flexibility, it issuitable for application when it is adhered to a material havingflexibility.

MODIFIED LOW MOLECULAR WEIGHT POLYOLEFIN (A)

The low molecular weight polyolefin to be used as the starting materialfor the modified low molecular weight polyolefin usable in the presentinvention has an intrinsic viscosity [η] of 0.01 dl/g to 1.0 dl/g, asmeasured at 135° C. in decalin. Examples of such a low molecular weightpolyolefin are homopolymers or copolymers of α-olefins such as ethylene,propylene, butene-1, hexene-1, 4-methyl-1-pentene, decene. As such anα-olefin, for example, straight or branched α-olefins having 2 to 10carbon atoms are preferred. Specifically, polyethylene, polypropylene,ethylene-propylene copolymer, poly-1-butene, poly-4-methyl-1-pentene,ethylene-propylene copolymer, ethylene-1-butene copolymer, andethylene-4-methyl-1-pentene copolymer are exemplified.

As the above-mentioned polyolefin having a relatively low molecularweight, those produced by a pyrolysis of polyolefins having a relativelyhigher molecular weight obtained by, for example, the high pressurepolymerization method or the medium, low pressure polymerization methodby using a transition metal compound catalyst, or high pressure methodpolyethylenes obtained by radical polymerization of the ethylene at ahigh pressure, or polyolefins obtained by the medium, low pressurepolymerization method in the presence of hydrogen by using a transitionmetal compound catalyst. These polyolefins may be in the form of asolid, liquid and wax, preferably in the form of wax and liquid.

The polyolefin wax as mentioned herein refers to a homopolymer of anα-olefin such as ethylene, propylene, 1-butene, 1-hexene,4-methyl-1-pentene, 1-decene, or a copolymer of two or more α-olefins,having an intrinsic viscosity of 0.03 to 1.0. For example, thepolyethylene wax obtained by pyrolysis of the high pressure methodpolyethylene, the high pressure polymerization polyethylene wax obtainedby radical polymerization of ethylene at a high pressure, thepolyethylene wax obtained by the medium, low pressure polymerization ofethylene or ethylene and the above α-olefin in the presence of atransition metal compound catalyst, or ethylene, α-olefin copolymer wax,polypropylene wax, poly-1-butene wax may be used. Among these polyolefinwaxes, polyolefin waxes composed mainly of ethylene are preferably used.

Furthermore, the low molecular weight liquid polyolefin may be anethylenic random copolymer formed from ethylene and an α-olefin having 3to 20 carbon atoms, having the content of ethylene component of 30 to 75mol %, preferably 40 to 70 mol %, and the content of α-olefin componentof 25 to 70 mol %, preferably 30 to 60 mol % (Note: the total of bothcomponents is 100 mol %). The ethylenic random copolymer has anintrinsic viscosity [η] as measured at 135° C. in decalin, which isgenerally in the range of from 0.01 to 0.3 dl/g, preferably from 0.03 to0.25 dl/g, a number average molecular weight is generally in the rangeof from 300 to 5,000, preferably from 500 to 4,000, and a molecularweight distribution (Mw/Mn), as measured by the GPC method, generally offrom 1.1 to 4, preferably from 1.2 to 3.

Specific examples of the α-olefin component are propylene, 1-butene,1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene,1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.Furthermore, liquid homopolymers of dienes as represented by butadiene,isoprene, chloroprene, or liquid or waxy copolymers of these dienes withstyrene or acrylonitrile, squalane can be exemplified.

According to the present invention, the low molecular weight polyolefinas described above can be modified by introducing (i) carboxylic groupor acid anhydride group or esters thereof, (ii) an aromatic vinylcompound or (iii) a nitrile compound. The modification may be carriedout by known methods such as graft reaction, copolymerization, of themonomer as described below, preferably by the former method.

As mentioned above, as the starting material for the modified lowmolecular weight polyolefin, liquid or waxy polyolefins are preferablyused. Of these, preferable are liquid or waxy modified ethylenic randomcopolymers which are liquid or waxy modified random copolymerscomprising (i) an unsaturated carboxylic acid derivative componentselected from the group consisting of unsaturated carboxylic acid hving3 to 10 carbon atoms and acid anhydride thereof and esters thereof, (ii)an aromatic vinyl compound or (iii) a nitrile compound graftcopolymerized onto ethylenic random copolymers constituted of ethyleneand an α-olefin having 3 to 20 carbon atoms.

The following description refers to the modified ethylenic randomcopolymer as an example, but the same description also applies to othermodified polymers.

The grafted ratio of the unsaturated carboxylic acid derivativecomponent in the modified ethylenic random copolymer is not particularlylimited, but the preferred grafted ratio with respect to an ameliorationof the mechanical properties and dispersibility in the epoxy resin maybe generally in the range from 0.2 to 50 parts by weight, preferablyfrom 0.5 to 40 parts by weight, based upon 100 parts by weight of theethylenic random copolymer. Specific examples of the unsaturatedcarboxylic acid derivative component unit having 3 to 10 carbon atomswhich is the graft copolymer component of the modified ethylenic randomcopolymer are unsaturated carboxylic acids such as acrylic acid,methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconicacid, tetrahydrophthalic acid,bicyclo[2,2,1]hepto-2-ene-5,6-dicarboxylic acid; anhydrides ofunsaturated carboxylic acids such as maleic anhydride, itaconicanhydride, citraconic anhydride, tetrahydrophthalic anhydride,[2,2,1]-hepto-2-ene-5,6-dicarboxylic acid anhydride; esters ofunsaturated carboxylic acids such as methyl acrylate, methylmethacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate,dimethyl itaconate, diethyl citraconate, dimethyl tetrahydrophthalicanhydride, dimethyl bicyclo-[2,2,1]hepto-2-ene-5,6-dicarboxylate. Ofthese, maleic anhydride is most preferably used.

Although the intrinsic viscosity [η] of the modified ethylenic randomcopolymer according to the present invention, as measured at 135° C. indecalin, is not particularly limited, an intrinsic viscosity of from0.01 dl/g to 1.0 dl/g, preferably from 0.01 to 0.3 dl/g, more preferablyfrom 0.03 to 0.25 dl/g is preferable in view of the amelioration effectof mechanical properties when formulated as the modifier of the epoxyresin. Also, the number average molecular weight of the liquid modifiedethylenic random copolymer is generally in the range of from 300 to5,000, preferably from 500 to 4,000. Furthermore, for the same reason,the molecular weight distribution (Mw/Mn) of the liquid modifiedethylenic random copolymer, as measured by gel permeation chromatography(GPC) is generally 4 or less, preferably in the range of from 1.2 to 3.Such a modified ethylenic random copolymer can be prepared by the methodproposed in Japanese Unexamined Patent Publication (Kokai) No. 57-123205by the present Applicant.

The aromatic vinyl and nitrile compounds usable for modifying themodified polyolefin which can be formulated in the epoxy resincomposition according to the present invention can be prepared by, forexample, graft polymerization of:

(1) 0 to 900 parts by weight, preferably 0 to 800 parts by weight, of anaromatic vinyl compound and 1 to 900 parts by weight, preferably 5 to800 parts by weight of a nitrile compound, or

(2) 1 to 900 parts by weight, preferably 5 to 800 parts by weight of anaromatic vinyl compound and 0 to 900 parts by weight, preferably 0 to800 parts by weight of a nitrile compound, based upon 100 parts byweight of the low molecular weight polyolefin, as mentioned above, in aconventional manner. Examples of such an aromatic vinyl compound arestyrene, α-methylstyrene, chlorostyrene, isopropenyltoluene,vinyltoluene, t-butylstyrene, divinylbenzene, and isopropenylphenol.

On the other hand, examples of the nitrile compound are acrylonitrile,methacrylonitrile and the like.

Although the intrinsic viscosity [η] of the aromatic vinyl/nitrilecompound modified low molecular weight polyolefin according to thepresent invention, as measured at 135° C. in decalin, is notparticularly limited, it is generally 0.03 to 1.0 dl/g, preferably 0.035to 0.8 dl/g in view of the amelioration effect of mechanical propertieswhen formulated as the modifier for the epoxy resin. Also, the numberaverage molecular weight of the modified polyolefin is generally in therange of from 300 to 15,000, preferably from 500 to 13,000. Themolecular weight distribution (Mw/Mn) of the modified polyolefin, asmeasured by gel permeation chromatography also is 4 or less, preferablyin the range of from 1.2 to 3, for the same reason.

EPOXY RESIN (B)

The epoxy resin (B) to be formulated into the epoxy resin composition ofthe present invention is a conventional epoxy resin comprising acompound containing 2 or more epoxy groups in one molecule. Examples ofsuch epoxy resins are glycidyl ether type epoxy resins of polyphenolcompounds such as bisphenol A, bisphenol F,1,1,2,2-tetrakis(4-hydroxyphenyl)-ethane and the like; glycidyl ethertype epoxy resins of polyhydric phenols such as catechol, resorcin,hydroquinone, fluoroglycine and the like; glycidyl ether type epoxyresins of polyhydric alcohols such as ethylene glycol, butane diol,glycerol, erythritol, polyoxyalkylene glycol and the like; novolac typeepoxy resins; cyclic aliphatic epoxy resins such as vinyl cyclohexenedioxide, limonene dioxide, dicylopentadiene dioxide and the like;polyglycidyl ester type epoxy resins of ester condensates ofpolycarboxylic acids such as phthalic acid, cyclohexane-1,2-dicarboxylicacid and the like; and polyglycidylamine type epoxy resins. Of theseepoxy resins, glycidyl ether type epoxy resins of polyphenol compoundsor novolac type epoxy resins are preferably formulated, and particularlypreferably, a glycidyl ether type epoxy resin of bisphenol A orbisphenol F are formulated.

CURING AGENT (C) FOR EPOXY RESIN

As the hardener (C) to be formulated in the epoxy resin composition ofthe present invention, any compounds generally known as the hardener forepoxy resins can be used. Specific examples of such hardeners are chainaliphatic polyamines such as diethylenetriamine, triethylenetetramine,tetraethylenepentamine, dipropylenediamine, diethylaminopropylamine;cyclic aliphatic polyamine; aliphatic polyamine adducts; keimine;modified aliphatic polyamines; polyamidoamines; aromatic amines;aromatic modified amines; aromatic modified polyamines; tertiary aminetype hardeners; mercaptan type hardeners; acid anhydride type hardeners;copolymers having acid anhydride groups such as ethylene-maleicanhydride copolymer; compounds having phenolic hydroxyl groups such asphenolic resin initial condensates; compounds such as dicyandiamide,melamine, boron trifluoride type complexes. Of these hardeners,dicyandiamine, aromatic polyamine such as diaminodiphenylmethane, borontrifluoride-amine complex compound are preferably used.

MONOAMINE COMPOUND (D)

Examples of the monoamine compound (D) to be formulated into the epoxyresin composition of the present invention are aliphatic primary aminessuch as propylamine, isopropylamine, butylamine, pentylamine,hexylamine, cyclohexylamine; aromatic primary amines such as aniline,toluidine, xylidine; secondary amines such as dimethylamine,diethylamine, dipropylamine, diisopropylamine, dibutylamine,dipentylamine, dicyclohexylamine, piperidine, N-methylaniline; tertiaryamines such as triethylamine, tripropylamine, tributylamine,dimethylbenzylamine; preferably secondary amines, particularly aliphaticsecondary amines, from the aspect of easy control of the pot life of thepresent composition.

COMPOSITION RATIOS OF RESPECTIVE COMPONENTS

The amount of the low molecular weight polyolefin (A) to be formulatedinto the epoxy resin composition of the present invention must be 1 to40 parts by weight from the standpoint of surface hardness and toughnessas well as impact strength and flexibility, preferably in the range offrom 3 to 30 parts by weight, based upon 100 parts by weight of thetotal amount thereof with the epoxy resin (B). Similarly, the amount ofthe epoxy resin (B) is 99 to 60 parts by weight, preferably in the rangeof from 97 to 70 parts by weight. On the other hand, the ratio of thehardener (C) formulated may be an adequate amount relative to the epoxyresin (B); as in the case of conventional epoxy resins, preferably 1 to300 parts by weight based upon 100 parts by weight of the modifiedpolyolefin.

On the other hand, when a monoamine compound is formulated, the amountof the monoamine compound (D) formulated is generally 0.01 to 20 partsby weight, preferably 0.1 to 10 parts by weight, based upon 100 parts byweight of the epoxy resin (B) in view of the reactivity and theviscosity of the composition.

PRODUCTION PROCESS OF THE EPOXY RESIN COMPOSITION

The epoxy resin composition of the present invention can be prepared bykneading the modified polyolefin (A) and the epoxy resin (B) previouslywhile heating, and then formulating the hardener at a temperature nothigher than the hardening temperature of the hardener (C). The amount ofthe unreacted epoxy resin (B), in the reaction between the modifiedpolyolefin (A) and the epoxy resin (B), is 1 part by weight or lessbased upon 100 parts by weight of the modified polyolefin (A), and theconditions of pre-blend therefor can be set generally at a kneadingtemperature of from 100° C. to 300° C. and a kneading time of from 1minute to 10 hours. These ranges may be determined by the combination ofthe three conditions, the kind of the modifying agent, the kneadingtemperature, and the kneading time, to satisfy the above condition.However, it is generally preferable to set the kneading temperature at110° C. to 250° C. and the kneading time at 2 minutes to 8 hours. By thekneading, the unreacted amount of the component (B) based upon 100 partsby weight of the component (A) should be made 1 part by weight or less,preferably 0.5 part by weight or less. If the conversion is lower andthe unreacted amount exceeds 1% by weight, problems arise in that, forexample, an improvement of the final cured product can not be obtainedand the adhesiveness is lowered. After kneading, the mixture of thecomponents (A) and (B) is cooled to a temperature not higher than thehardening temperature of the hardener, followed by addition of thehardener and, then, the resultant mixture is kneaded at thattemperature. Thus the epoxy resin composition of the present inventionis obtained. Also, if necessary, fillers, pigments, stabilizers, curingaccelerators, thixotropic agents, flow controllers, and the like can beformulated.

On the other hand, when the monoamine compound (D) is formulatedaccording to the present invention, the modified low molecular weightpolyolefin (A), the epoxy resin (B), and the monoamine compound (D) arepreviously reacted together by kneading at ordinary temperature to 200°C., preferably while heating, as mentioned below, and then formulatedwith the hardener (C) at a temperature not higher than the hardeningtemperature of the hardener to prepare the composition. The reactionconditions of the modified polyolefin (A), the epoxy resin (B), and themonoamine compound (D) can be set preferably at a kneading temperatureof from ordinary temperature to 150° C. and a kneading time of from 1minute to 10 hours. These ranges may be determined by the combination ofthe kind of epoxy resin, the kind of modifying agent, the kind ofmonoamine compound (D), the kneading temperature, and the kneading time,to satisfy the above conditions. However, it is generally preferable toset the kneading temperature at ordinary temperature to 180° C. and thekneading time at 2 hours to 8 hours. Although the order of mixing thecomponents (A), (B) and (D) is not particularly limited, the method asshown below in the Examples is preferred. After kneading, the mixture ofthe components (A), (B) and (D) is cooled to a temperature not higherthan the hardening temperature of the hardener, followed by addition ofthe hardener and, then, the resultant mixture is kneaded at thattemperature to give the epoxy resin composition of the presentinvention.

OTHERS

The epoxy resin composition according to the present invention can beutilized for usages such as paints, particularly powdery paint, surfacecoating agents, adhesives, molding materials. For example, it can beused when applied by the electrostatic coating method, the fluid dippingmethod, the press method, the extrusion molding method, the injectionmolding method, the casting method, the impregnation method, and thecoating method with a solution.

As is clear from the above-mentioned explanation and the Examples shownbelow, the epoxy resin composition according to the present inventionhas an extremely strong impact resistance, and an excellent waterresistance, chemical resistance, rust resistance, oxidation resistance,compared with epoxy resins or compositions containing other modifiersadded thereto, and further the applied coating has a good appearancewhen used for paints.

EXAMPLES

The epoxy resin composition of the present invention and the productionprocess thereof are described in detail below by referring to Examples.

The modified liquid ethylene-propylene random copolymers used inExamples 1 to 3 and Comparative Examples 1 to 6 are obtained by graftreaction according to the conventional method, using a liquidethylenepropylene random copolymer with an ethylene/propylenecomposition ratio=50/50 mol %, a number average molecular weight of 810,[η]=0.04 dl/g and Mw/Mn=1.40, and di-tert-butyl peroxide as theinitiator.

Also, the unreacted modified liquid polyolefin remained in thecomposition was quantitatively determined by liquid chromatography.

The peel-off test was conducted at a temperature of 23° C. and accordingto ASTM D1876-72. The T peel-off strength was tested by using analuminum foil with a thickness of 50μ as the material to be adhered.

EXAMPLE 1

To 90 g of a bisphenol-type epoxy resin (EPOMIK® R-304, produced byMitsui Petrochemical Industries Ltd., epoxy equivalent 875-1,000,softening point 93°-104° C.) was added 10 g of a liquidethylene-propylene random copolymer grafted with maleic anhydride(maleic anhydride content 10% by weight, ethylene/propylene compositionratio=50/50 mol %, number average molecular weight 810, [η]=0.04 dl/g,Mw/Mn=1.40) and the mixture was kneaded by a kneader under a nitrogenatmosphere at a temperature of 200° C. for 60 minutes. Unreactedmodified liquid polyolefin in the kneaded composition was quantitativelydetermined by liquid chromatography. Subsequently, after cooling to 110°C., 3.6 g of dicyandiamide was added and the mixture was kneadedfollowed by pulverization to obtain a thermosetting composition. Thecomposition was cured by heating at a temperature of 200° C. under apressure of 60 kg/cm² for 10 minutes, and a measurement of the unnotchedIzod impact strength and peel-off strength at 23° C. according to ASTMD-256 of the cured molding obtained was carried out. The results areshown in Table 1.

EXAMPLES 2 TO 4

Under the same conditions as in Example 1, except that the kneading timewas 60 minutes in Example 1 but 30 minutes in this example, theintermediate thermosetting composition and the thermally cured moldingwere obtained. Similarly, the kneading time and the kneading temperaturewere changed as shown in Table 1 under Examples 3 and 4. The results areshown in Table 1.

EXAMPLE 5

A thermosetting composition was obtained under the same conditions as inExample 1, except that an acrylic acid adduct of a liquidethylene-propylene copolymer (acrylic acid content 5% by weight, numberaverage molecular weight 810, [η]=0.04, Mw/Mn=1.40) was used instead ofthe maleic anhydride adduct of the liquid ethylene-propylene copolymerin Example 1.

COMPARATIVE EXAMPLE 1

A thermosetting composition was obtained under the same conditions as inExample 1, except that the unmodified liquid ethylene-propylenecopolymer (number average molecular weight 810, [η]=0.04, Mw/Mn=1.40)was used instead of the maleic anhydride adduct of the liquidethylene-propylene copolymer in Example 1.

COMPARATIVE EXAMPLE 2

A thermosetting composition was obtained under the same conditions as inExample 1, except that a polyethylene wax modified with maleic anhydride(maleic anhydride content 5% by weight, number average molecular weight1,400, [η]=0.05, Mw/Mn=2.86) was used instead of the maleic anhydrideadduct of the liquid ethylene-propylene copolymer in Example 1.

COMPARATIVE EXAMPLE 3

A thermosetting composition was obtained under the same conditions as inExample 1, except that an unmodified polyethylene wax (number averagemolecular weight 1,000, [η]=0.04, Mw/Mn=2.00) was used instead of themaleic anhydride adduct of the liquid ethylenepropylene copolymer inExample 1.

COMPARATIVE EXAMPLE 4

A thermosetting composition was obtained under the same conditions as inExample 1, except that the graft adduct of Example 1 was not added.

The unnotched Izod impact strength and peel-off strength for these nineExamples are shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________                   Example                    Comparative Example                                1    2    3    4     5     1     2     3    4                  __________________________________________________________________________    Epoxy resin amount                                                                           100  100  100  100   100   100   100   100  100                (parts by weight)                                                             (Liquid)                                                                            Base polymer                                                                           Liquid                                                                             Liquid                                                                             Liquid                                                                             Liquid                                                                              Liquid                                                                              Liquid                                                                              Poly- Poly-                                                                              --                 Modified       ethylene-                                                                          ethylene-                                                                          ethylene-                                                                          ethylene-                                                                           ethylene-                                                                           ethylene-                                                                           ethylene                                                                            ethylene                polyolefin     propy-                                                                             propy-                                                                             propy-                                                                             propylene                                                                           propylene                                                                           propylene                                                                           wax   wax                                    lene lene lene copolymer                                                                           copolymer                                                                           copolymer                                          copol-                                                                             copol-                                                                             copol-                                                              ymer ymer ymer                                                       Grafted  Maleic                                                                             Maleic                                                                             Acrylic                                                                            Maleic                                                                              Maleic                                                                              --    Maleic                                                                              --   --                       monomer  anhy-                                                                              anhy-                                                                              acid anhydride                                                                           anhydride   anhydride                                    dride                                                                              dride                                                           Grafted  10   10   10   10    10    --    5     --   --                       amount (wt %)                                                                          0.04 0.04 0.04 0.04  0.04  0.04  0.05  0.04 --                       [η] (dl/g)                                                                Number average                                                                         810  810  810  810   810   810   1400  1000 --                       molecular weight                                                                       1.40 1.40 1.40 1.40  1.40  1.40  2.86  2.00 --                       --Mw/--Mn                                                                     Amount added                                                                           11   11   11   11    11    11    11    11   0                        (parts by weight)                                                       Hardener (dicyandiamide)                                                                     4    4    4    4     4     4     4     4    4                  amount (parts by weight)                                                      Kneading temperature (°C.)                                                            200  200  200  200   110   200   200   200  200                Kneading time (min.)                                                                         60   30   60   10    60    60    60    60   60                 Unreacted liquid modified                                                                    0.1  0.6  0.3  1.2   7.3   11*   0.3   0    0                  polyolefin (parts by weight)                                                  Unnotched Izod impact                                                                        31   28   29   28    4.5   4.8   4.2   2.2  4.9                strength (kg · cm/cm)                                                Peel-off strength (kg/25 mm)                                                                 2.5  1.7  1.9  0.1   0.05  2.9   1.8   2.8  3.0                __________________________________________________________________________     *Quantitative value of unmodified liquid polyolefin                      

EXAMPLE 6

Using a liquid ethylene-propylene random copolymer (ethylene/propylenecomposition ratio=50/50 mol %, number average molecular weight 810,[η]=0.004 dl/g, Mw/Mn=1.40) as the base polymer and di-tert-butylperoxide as the initiator, maleic anhydride was grafted to obtain aliquid ethylene-propylene random copolymer modified with maleicanhydride, at a 10% by weight grafted ratio of the maleic anhydride. Anamount of 10 parts by weight of the modified liquid ethylene-propylenerandom copolymer and 90 parts by weight of a bisphenol type epoxy resin(EPOMIK® R-304, produced by Mitsui Petrochemical Industries Ltd., epoxyequivalent 875-1,000, softening point 93°-104° C.) were placed in akneader, and while kneading at a temperature of 110° C., 1.3 parts byweight of di-n-butylamine were added and kneaded for 40 minutes, andthen 3.6 parts by weight of dicyandiamine were added, followed bykneading for a further 5 minutes.

Then, the mixture was taken out of the kneader and pulverized to give athermosetting composition. The composition was cured by heating at atemperature of 200° C. under a pressure of 60 kg/cm² for 10 minutes, andunnotched Izod impact strength according to ASTM D256 of the obtainedcured molding was measured. Also, using a 50 μm aluminum foil as thematerial to be adhered, the T peel-off strength was measured accordingto ASTM D1876-72. The thickness of the adhesive layer was 50 μm. Theresults are shown in Table 2.

EXAMPLE 7

The same procedure as in Example 6 was repeated, except thatdi-n-butylamine in Example 6 was changed to 1.0 part by weight oftri-n-butylamine.

EXAMPLE 8

The same procedure as in Example 6 was repeated, except thatdi-n-butylamine in Example 6 was changed to 1.0 part by weight ofn-hexylamine.

EXAMPLE 9

The same procedure as in Example 6 was repeated, except thatdi-n-butylamine in Example 6 was not added.

EXAMPLE 10

A 10 parts by weight amount of the modified liquid ethylene-propylenerandom copolymer and 90 parts by weight of the bisphenol type epoxyresin used in Example 6 were placed in a kneader and kneaded, withoutthe addition of the amine, at a temperature of 200° C. for 40 minutes.Then, the temperature was lowered to 110° C., and 1.3 parts by weight ofdicyandiamine were added and further kneaded for 5 minutes. The mixturewas then withdrawn and pulverized to obtain a thermosetting resincomposition. The evaluation results are shown in Table 2. As is clearfrom the results shown in the Table, when a monoamine compound is notadded, although disadvantageous in practice, the peel-off strength isincreased by raising the kneading temperature, but remains considerablylower than when a monoamine compound is added.

EXAMPLE 11

A liquid ethylene-propylene copolymer modified with acrylic acid with 8%by weight of the acrylic acid grafted ratio was obtained by graftingacrylic acid to the liquid ethylene-propylene random copolymer used inExample 6 by using the use of di-tert-butyl peroxide as the initiator.Using the ethylene-propylene copolymer modified with acrylic acid inplace of the ethylenepropylene copolymer modified with maleic anhydridein Example 6, a thermosetting resin composition was obtained by kneadingby the same procedure used in Example 6. The results are shown in Table2.

EXAMPLE 12

The procedure of Example 11 was entirely repeated, except thatdi-n-butylamine was not added. The results are shown in Table 2.

EXAMPLE 13

To a liquid polybutadiene with a cis-1,4-linkage content of 85% or moreand a number average molecular weight of 1,200 was grafted maleicanhydride by using di-tert-butyl peroxide as the initiator, to obtain amodified liquid polybutadiene with a grafted ratio of maleic anhydrideof 10% by weight. Using the modified liquid polybutadiene instead of themodified liquid ethylene-propylene in Example 6, the same operation asin Example 6 was carried out to obtain a thermosetting resincomposition. The results ar shown in Table 2.

COMPARATIVE EXAMPLE 5

The unnotched Izod impact strength and peel-off strength of thebisphenol type epoxy resins used in Examples 6-12 were then measured.The curing conditions are the same as in Example 6 and the results areshown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________                                                            Comparative                         Example                                   Example                             6    7    8    9    10   11   12    13    5                     __________________________________________________________________________    Epoxy resin amount                                                                          90   90   90   90   90   90   90    90    100                   (parts by weight)                                                             (Liquid)                                                                            Base polymer                                                                          Liquid                                                                             Liquid                                                                             Liquid                                                                             Liquid                                                                             Liquid                                                                             Liquid                                                                             Liquid                                                                              Liquid-                                                                             --                    Modified      ethylene-                                                                          ethylene-                                                                          ethylene-                                                                          ethylene-                                                                          ethylene-                                                                          ethylene-                                                                          ethylene-                                                                           poly-                       polyolefin    propy-                                                                             propy-                                                                             propy-                                                                             propy-                                                                             propy-                                                                             propy-                                                                             propylene                                                                           butadiene                                 lene lene lene lene lene lene                                                 copol-                                                                             copol-                                                                             copol-                                                                             copol-                                                                             copol-                                                                             copol-                                                                             copolymer                                       ymer ymer ymer ymer ymer ymer                                         Grafted Maleic                                                                             Maleic                                                                             Maleic                                                                             Maleic                                                                             Maleic                                                                             Acrylic                                                                            Acrylic                                                                             Maleic                                                                              --                          monomer anhy-                                                                              anhy-                                                                              anhy-                                                                              anhy-                                                                              anhy-                                                                              acid acid  anhydride                                 dride                                                                              dride                                                                              dride                                                                              dride                                                                              dride                                             Grafted 10   10   10   10   10   8    8     10    --                          amount (wt %)                                                                         0.04 0.04 0.04 0.04 0.04 0.04 0.04  0.05  --                          [η] (dl/g)                                                                Number-aver-                                                                          810  810  810  810  810  810  810   1200  --                          age molecular                                                                 weight                                                                        --Mw/--Mn                                                                             1.40 1.40 1.40 1.40 1.40 1.40 1.40  1.50  --                          Amount added                                                                          10   10   10   10   10   10   10    10    --                          (parts by                                                                     weight)                                                                 Amine         di-n-                                                                              tri-n-                                                                             n-hexyl-                                                                           --   --   di-n-                                                                              --    di-n- --                                  butyl-                                                                             butyl-                                                                             amine          butyl-     butyl-                                    amine                                                                              amine               amine      amine                       Amount of amine                                                                             1.3  1.0  1.0  --   --   1.3  --    1.3   --                    (parts by weight)                                                             Kneading temperature (°C.)                                                           110  110  110  110  200  110  110   110   --                    Kneading time (min.)                                                                        45   45   45   45   45   45   45    45    --                    Hardener (dicyandiamide)                                                                    3.6  3.6  3.6  3.6  3.6  3.6  3.6   3.6   4                     amount (parts by weight)                                                      Unnotched Izod impact                                                                       38.5 35.0 28.0 4.5  28.0 34.0 4.4   27.0  4.9                   strength (kg · cm/cm)                                                Peel-off strength (kg/25 mm)                                                                3.4  3.0  2.5  0.05 2.0  3.1  0     3.0   3.0                   __________________________________________________________________________

REFERENCE EXAMPLE 1

A 100 parts by weight amount of a polyethylene wax having an intrinsicviscosity of 0.08 dl/g (Mitsui Highwax 110p, produced by MitsuiPetrochemical Industries Ltd.) was charged into a pressure type glassreactor and dissolved at a temperature of 140° C. Then, 25 parts byweight of styrene monomer and 5.8 parts by weight of di-tert-butylperoxide were added by a dropping funnel over 4 hours, and then thereaction was carried out for one hour, followed by degassing treatmentin vacuum of 5 mmHg under the molten state for one hour to remove thevolatiles, and the product was thereafter cooled. The styrene-graftedwax thus obtained was dissolved in p-xylene, reprecipitated with methylethyl ketone. After purification by repeating this procedure, thegrafted amount was determined by NMR spectrum and IR absorptionspectrum. As the result, the amount of styrene grafted was found to be25 parts by weight based upon 100 parts by weight of the polyethylenewax.

REFERENCE EXAMPLES 2 TO 4

In Reference Example 1, the kind of the graft monomer and amount thereofwere changed as shown in Table 3, but otherwise the same procedure wasfollowed as in Reference Example 1.

REFERENCE EXAMPLES 5 TO 6

In Reference Example 1, a liquid ethylene-propylene copolymer(composition: ethylene 50 mol %, propylene 50 mol %, [η]: 0.04 dl/g,number average molecular weight 800, Mw/Mn 1.4) was used instead of thepolyethylene wax, and the amount of the monomer grafted was changed asshown in Table 3, but otherwise the same procedure was followed as inReference Example 1.

REFERENCE EXAMPLE 7

Reference Example 1 was entirely repeated, except that the intrinsicviscosity of polyethylene wax was changed to 0.52 dl/g and the amount ofthe monomer grafted was changed to that shown in Table 3.

EXAMPLES 13 TO 19

Into a kneader set at a temperature of 100° C. 100 parts by weight of anepoxy resin (EPOMIK® R364, Mitsui Petrochemical Industries Ltd.), 11parts by weight of a modified polyolefin and 4 parts by weight ofdicyanamide were fed, and kneading was carried out at a screw rotationalnumber of 50 rpm for 15 minutes to obtain an epoxy resin composition.Then, the composition was cured by heating at a temperature of 200° C.under a pressure of 60 kg/cm² for 10 minutes by a hot press.

The physical properties of the cured composition were evaluatedaccording to the following methods.

[1] Izod impact strength: Measured according to ASTM D-256 using a teststrip with a thickness of 1/8 inch.

[2] Peel-off strength . . . Using two sheets of soft aluminum (thickness50μ, 20 cm square) as the material to be adhered, with a spacer of 50μin thickness and 5 g of a sample therebetween, adhesion was effectedunder the above curing conditions. Then, a test strip was cut to a widthof 25 mm, and the peel-off test was conducted under a cross-head speedof 250 mm/min.

[3] Melt viscosity . . . Melt viscosity at a temperature of 150° C. wasmeasured by an Emylar rotatory viscometer.

COMPARATIVE EXAMPLES 6 TO 7

In Example 13, a polyethylene wax (Comparative Example 6) or anethylene-propylene copolymer (Comparative Example 7) was used instead ofthe modified polyolefin, but otherwise the same procedure was followedas in Example 13. The results are shown in Table 3.

COMPARATIVE EXAMPLE 8

In Example 13, the modified polyolefin was not used, but otherwise thesame procedure was followed as in Example 13. The results are shown inTable 3.

                                      TABLE 3                                     __________________________________________________________________________                        Example                 Comparative                                                                                 Example                                 13  14  15  16  17  18  1    2    3   19                  __________________________________________________________________________    Epoxy resin amount (parts by weight)                                                              100 100 100 100 100 100 100  100  100 100                 Epoxy                                                                              Modi-                                                                             Kind       Refer-                                                                            Refer-                                                                            Refer-                                                                            Refer-                                                                            Refer-                                                                            Refer-                                                                            Poly-                                                                              Ethyl-                                                                             --  Refer-              resin                                                                              fied           ence                                                                              ence                                                                              ence                                                                              ence                                                                              ence                                                                              ence                                                                              ethylene                                                                           ene-     ence                Compo-                                                                             poly-          Exam-                                                                             Exam-                                                                             Exam-                                                                             Exam-                                                                             Exam-                                                                             Exam-                                                                             wax  propy-   Exam-               sition                                                                             olefin         ple 1                                                                             ple 2                                                                             ple 3                                                                             ple 4                                                                             ple 5                                                                             ple 6    lene co- ple 7                                                                polymer                               Base polyolefin [η]                                                                   0.08                                                                              0.08                                                                              0.08                                                                              0.08                                                                              0.04                                                                              0.04                                                                              0.08                                                                               0.04                                                                              --   0.52                        (dl/g)                                                                        Monomer                                                                             Styrene                                                                            25  70   35 120 25  50  0    0    --  25                           added*.sup.1                                                                        Metha-                                                                              0   0  35  120  0  50  0    0    --   0                           (wt. parts)                                                                         crylo-                                                                        nitrile                                                                 Grafted                                                                             Styrene                                                                            25  67  33  117 25  50  0    0    --  25                           amount*.sup.1                                                                       Metha-                                                                              0   0  33  117  0  50  0    0    --   0                           (wt. parts)                                                                         crylo-                                                                        nitrile                                                                 Addition amount                                                                          11  11  11   11 11  11  11   11    0  11                           (wt. parts)                                                          Hardener (dicyandiamide)                                                                           4   4   4   4   4   4  4    4     4   4                  (parts by weight)                                                             Physical Izod impact                                                                         Notched                                                                            5.6 6.4 5.8 7.1 6.2 6.0 2.0  2.0  2.0 6.5                 properties                                                                             strength                                                                            Un-  46  41  47   46 48  47  4.8  4.8  4.9 52                           (kg · cm/                                                                  notched                                                                 cm)                                                                           Peel-off strength                                                                        2.7 2.5 3.1 3.3 2.8 3.4 2.8  2.9  3.0 3.0                          (kg/25 mm)                                                                    150° C. Melt viscosity                                                            4300                                                                              5300                                                                              7000                                                                              7200                                                                              4300                                                                              6000                                                                              4500 4500 4700                                                                              13000               __________________________________________________________________________     *.sup.1 Amount added based on 100 parts by weight of base polyolefin     

I claim:
 1. An epoxy resin composition comprising:(A) 1 to 40 parts byweight of a modified low molecular weight polyolefin obtained by graftcopolymerizing at least one graft monomer selected from the groupconsisting of:(i) at least one unsaturated carboxylic acid derivativeselected from the group consisting of unsaturated carboxylic acids andanhydrides thereof and esters thereof, (ii) at least one aromatic vinylcompound, and (iii) at least one nitrile compound, onto a low molecularweight polyolefin having an intrinsic viscosity [η] of 0.01 dl/g to 1.0dl/g, as measured in decalin at a temperature of 135° C., (B) 99 to 60parts by weight of an epoxy resin (the total amount of (A) an (B) is 100parts by weight), and (C) a hardener for the epoxy resin.
 2. Acomposition as claimed in claim 1, wherein said low molecular weightpolyolefin is an ethylenic random copolymer consisting of 30 to 75 mol %of ethylene component and 25 to 70 mol % of an α-olefin component having3 to 20 carbon atoms.
 3. A composition as claimed in claim 1, whereinthe low molecular weight polyolefin (A) comprises 0.2 to 50 parts byweight of at least one unsaturated carboxylic acid derivative componentselected from the group consisting of unsaturated carboxylic acidshaving 3 to 10 carbon atoms and anhydrides thereof and esters thereofgrafted onto 100 parts by weight of said low molecular weightpolyolefin.
 4. A composition as claimed in claim 3, wherein the modifiedlow molecular weight polyolefin (A) has an intrinsic viscosity [η] of0.01 to 0.3 dl/g, as measured in decalin at a temperature of 135° C. anda molecular weight distribution (Mw/Mn) of 4 or less, as measured by gelpermeation chromatography.
 5. A composition as claimed in claim 1,wherein the modified low molecular weight polyolefin (A) comprises 1 to900 parts by weight of an aromatic vinyl compound and 0 to 900 parts byweight of a nitrile compound grafted onto 100 parts by weight of saidlow molecular weight polyolefin.
 6. A composition as claimed in claim 5,wherein the modified low molecular weight polyolefin (A) has anintrinsic viscosity [η] of 0.03 to 1.0 dl/g, as measured in decalin at atemperature of 135° C. and a molecular weight distribution (Mw/Mn) of 4or less, as measured by gel permeation chromatography.
 7. A compositionas claimed in claim 1, wherein the modified low molecular weightpolyolefin (A) comprises 0 to 900 parts by weight of an aromatic vinylcompound and 1 to 900 parts by weight of a nitrile compound grafted onto100 parts by weight of said low molecular weight polyolefin.
 8. Acomposition as claimed in claim 7, wherein the modified low molecularweight polyolefin (A) has an intrinsic viscosity [η] of 0.03 to 1.0dl/g, as measured in decalin at a temperature of 135° C. and a molecularweight distribution (Mw/Mn) of 4 or less, as measured by gel permeationchromatography.
 9. A process for producing an epoxy resin composition,comprising the steps of: kneading, while heating,(A) 1 to 40 parts byweight of a modified low molecular weight polyolefin obtained by graftcopolymerizing at least one graft monomer selected from the groupconsisting of:(i) at least one unsaturated carboxylic acid derivativeselected from the group consisting of unsaturated carboxylic acids andanhydrides thereof and esters of these, (ii) at least one aromatic vinylcompound, and (iii) at least one nitrile compound, onto a low molecularweight polyolefin having an inherent viscosity [η] of 0.01 dl/g to 1.0dl/g, as measured in decalin at a temperature of 135° C., and (B) 99 to60 parts by weight of an epoxy resin (the total amount of (A) and (B) is100 parts by weight) to make the unreacted amount of the component (B)based upon 100 parts by weight of the component (A) part by weight orless, and then formulating a hardener (C) at a temperature not higherthan the hardening temperature of the hardener (C), whereby an epoxyresin composition containing the components (A), (B) and (C) isproduced.
 10. An epoxy resin composition comprising:(A) 1 to 40 parts byweight of a modified low molecular weight polyolefin obtained by graftcopolymerizing at least one graft monomer selected from the groupconsisting of:(i) at least one unsaturated carboxylic acid derivativeselected from the group consisting of unsaturated carboxylic acids andanhydrides thereof and esters thereof, (ii) at least one aromatic vinylcompound, and (iii) at least one nitrile compound, onto a low molecularweight polyolefin having an inherent viscosity [η] of 0.01 dl/g to 1.0dl/g, as measured in decalin at a temperature of 135° C., (B) 99 to 60parts by weight of an epoxy resin (the total amount of (A) and (B) is100 parts by weight), (C) a hardener for the epoxy resin, and (D) 0.01to 20 parts by weight of a monoamine compound.
 11. A composition asclaimed in claim 10, wherein said low molecular weight polyolefin is anethylenic random copolymer consisting of 30 to 75 mol % of ethylenecomponent and 25 to 70 mol % of an α-olefin component having 3 to 20carbon atoms.
 12. A composition as claimed in claim 11, wherein the lowmolecular weight polyolefin (A) comprises 0.2 to 50 parts by weight ofat least one unsaturated carboxylic acid derivative component selectedfrom the group consisting of unsaturated carboxylic acids having 3 to 10carbon atoms and anhydrides thereof and esters thereof grafted onto 100parts by weight of said low molecular weight polyolefin.
 13. Acomposition as claimed in claim 12, wherein the modified low molecularweight polyolefin (A) has an intrinsic viscosity [η] of 0.01 to 0.3dl/g, as measured in decalin at a temperature of 135° C. and a molecularweight distribution (Mw/Mn) of 4 or less, as measured by gel permeationchromatography.
 14. A composition as claimed in claim 1, wherein themodified low molecular weight polyolefin (A) comprises 1 to 900 parts byweight of an aromatic vinyl compound and 0 to 900 parts by weight of anitrile compound, grafted onto 100 parts by weight of said low molecularweight polyolefin.
 15. A composition as claimed in claim 14, wherein themodified low molecular weight polyolefin (A) has an intrinsic viscosity[η] of 0.03 to 1.0 dl/g, as measured in decalin at a temperature of 135°C. and a molecular weight distribution (Mw/Mn) of 4 or less, as measuredby gel permeation chromatography.
 16. A composition as claimed in claim1, wherein the modified low molecular weight polyolefin (A) comprises 0to 900 parts by weight of an aromatic vinyl compound and 1 to 900 partsby weight of a nitrile compound, grafted onto 100 parts by weight ofsaid low molecular weight polyolefin.
 17. A composition as claimed inclaim 16, wherein the modified low molecular weight polyolefin (A) hasan intrinsic viscosity [η] of 0.03 to 1.0 dl/g, as measured in decalinat a temperature of 135° C. and a molecular weight distribution (Mw/Mn)of 4 or less, as measured by gel permeation chromatography.
 18. Aprocess for producing an epoxy resin composition comprising the stepsof:kneading, while heating, (A) 1 to 40 parts by weight of a modifiedlow molecular weight polyolefin obtained by graft copolymerizing atleast one graft monomer selected from the group consisting of:(i) atleast one unsaturated carboxylic acid derivative selected from the groupconsisting of unsaturated carboxylic acids and anhydrides thereof andesters thereof, (ii) at least one aromatic vinyl compound, and (iii) atleast one nitrile compound, onto a low molecular weight polyolefinhaving an inherent viscosity [η] of 0.01 dl/g to 1.0 dl/g, as measuredin decalin at a temperature of 135° C., (B) 99 to 60 parts by weight ofan epoxy resin (the total amount of (A) and (B) is 100 parts by weight,and (D) 0.01 to 20 parts by weight of a monoamine compound, to carry outthe reaction and thereafter, formulating a hardener (C) at a temperaturenot higher than the hardening temperature of the hardener (C), wherebyan epoxy resin composition containing the components (A), (B), (C) and(D) is produced.